There is a screen printing device configured in such a manner that a stencil (mask) for screen printing is superimposed on a substrate and paste, such as cream solder, supplied on the stencil is spread by sliding the squeegee along the surface of the stencil, so that the cream solder is printed (applied) onto the substrate at predetermined positions via openings (pattern holes) made in the stencil.
In the printing device configured as above, when the squeegee is slid over the stencil, the position of the stencil may possibly be displaced due to frictional resistance associated with the sliding.
In a screen printing device disclosed in Patent Document 1, suction holes are provided to the surfaces of clamps that hold a substrate from the both sides and the stencil is fixed by attracting the stencil to the clamps by setting the suction holes to a negative pressure at the time of printing. It thus becomes possible to prevent positional displacement of the stencil.
In the printing device disclosed in Patent Document 1, however, attracted portions of the stencil are deformed due to a negative pressure and hollows are formed therein. When the squeegee passes over these hollows, part of cream solder scraped up on the front side (scraping face side) of the squeegee goes round to the rear side of the squeegee via the hollows. The squeegee then moves over the stencil while trailing the cream solder present on the rear side. When the cream solder migrates by being trailed by the squeegee in this manner, thread-like cream solder adheres onto the stencil. This causes the cream solder to be applied exceedingly or insufficiently and poses a problem that the printing accuracy is deteriorated.
It should be appreciated, however, that even with the configuration of Patent Document 1, in a case where a sucking force by the clamps is reduced, no hollows will be formed in the stencil due to a negative pressure. Hence, even when the squeegee passes over the attracted portions, it is possible to prevent cream solder from going round to the rear side.
Reducing a sucking force, however, deteriorates a holding force for the stencil. Accordingly, when the squeegee is slid over the stencil, the position of the stencil is displaced due to sliding resistance. It is therefore impossible to solve the initial problem that poor printing occurs.
Patent Document 1: Japanese Patent Unexamined Publication No. HEI5-185580 (Columns 4 and 5 and FIGS. 1 and 2)